1. Field of the Invention
The present invention relates to the field of frequency doubling circuits for sinusoidal and cosinusoidal signals emitted by an angular step generator.
2. Description of the Prior Art
The prior art publication "A New Optoelectronic Angular Step Generator for Control Tasks" of the "Component Report" 16 (1978), issue 1, pp. 1-5, describes the basic functioning of an angular step generator. With such an angular step generator, two 90.degree. out-of-phase sinusoidal or cosinusoidal signals can be tapped. These signals are generated by the optical scanning of an impulse disk which is provided with slots. The resolution capacity of such an angular step generator is dependent upon the number of dashes or slots on the impulse disk.
As a measure for increasing the resolution, it is known in the prior art that the sinusoidal and cosinusoidal signals are respectively transformed into a square-wave signal. These signals, as well as their complementary pulses, pass through four monostable multivibrators which transform each falling edge of one of the pulses into an impulse of defined length. This then creates a series of impulses of equal duration. This configuration, however, does not produce an output signal with a 1:1 pulse duty factor.
It is therefore possible to increase the diameter of the impulse disks, so as to increase the number of markings. However, this measure increases the space requirements as well as the costs.
It is the object of the present invention to increase the resolution of an angular step generator, while the output pulse maintains a 1:1 pulse duty factor.